804
FXAK68 PAFC 221344
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
544 AM AKDT Wed May 22 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

Cool and mostly cloudy weather is expected for much of southcentral
Alaska over the next few days. Satellite imagery currently shows a
large upper-level low currently positioned across western Alaska
with one potent shortwave trough now ejecting east towards Yukon.
Precipitation associated with this trough has brought fairly
widespread rain (/high elevation snow) to the area over the past
24 hours, particularly along the coast where frontal precip +
upsloping flow has resulted in approximately 0.25 to 1 inch of
rain for much of the coastal communities along the Gulf of
Alaska. While the primary band shifts east towards Yakutat,
lingering precip along the Gulf Coast of the Kenai and Prince
William Sound will pick back up later today, if it ever stops to
begin with, as another shortwave trough begins to rotate across
the area.

Rain, lighter in intensity than along the coast, will also shift
north up through the Kenai Peninsula later today and eventually
towards Anchorage and the Mat-Su Valley. For much of the day,
coastal ridging will continue to drive strong SE flow through the
mountain gaps and Turnagain Arm. Downsloping, drying air may keep
much, if not most, precip from falling to the surface on the
west/north side of the mountains.

The pressure gradient will relax tonight as a low develops across
the north Gulf Coast in tandem with the primary upper-level trough
axis shifting east. This will result in the strong Turnagain, Knik,
and Copper River Basin winds gradually abating late today and
tonight. Precipitation will pick up late tonight into tomorrow along
the Richardson and Tok highways, north and east of Glennallen.
Snowflakes may be seen down to approximately 2000` with some light
snow accumulation towards Isabel and Mentasta passes.

Outside of the Copper River Basin, much of Thursday will be dry or
mostly dry for the area as ridging briefly moves overhead. This will
be shortlived as the last weather-making upper-level low is quickly
replaced with another. Precipitation will persist across the Gulf of
Alaska coastal communities for much of Friday, with areas away from
the Gulf also having a chance to receive at least some rain. One
thing is for sure: it`ll remain cloudy for the days to come with
temperatures remaining near or below climatological average.

-Brown

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA, BERING SEA/ALEUTIANS
(Days 1 through 3: Today through Friday)...

Two storms move across the Bering Sea, Aleutian Islands, and
Southwest Alaska through Friday, keeping unsettled weather in the
forecast. Forecast confidence is relatively high; the biggest
challenge will be forecasting minor snow accumulations for the
Pribilof Islands and Kuskokwim Delta coast before precipitation
changes over to rain late tonight into Thursday morning. No major
hazards are being monitored at this time.

The first storm is an occluded low currently moving onshore near
Nunivak Island. Widespread showers across Southwest Alaska this
morning will gradually taper off through the day. With cold air
wrapping around the backside of the low and streaming in aloft,
expect temperatures across Southern Alaska and the Pribilof
Islands to dip near freezing tonight and early tomorrow morning.

The second storm is a moderately strong low moving towards the
Western Aleutians. Its front extends out ahead of it and is
currently approaching the Central Aleutians. As the front treks
eastward, lingering cold air will bring the potential for light
snow accumulations along the Pribilof Islands late tonight, and
for Nunivak Island and the Kuskokwim Delta coastline on Thursday
morning. In addition to precipitation, this low will also bring a
broad swath of gales and showers as cold air wraps back around the
low. These stronger winds move across the Central Aleutians
Thursday morning, then weaken as they move over the Eastern
Aleutians Thursday evening. By Friday, widespread showers spread
across Southwest Alaska as the occluding low center moves onshore.

-KC

&&


.LONG TERM FORECAST (Days 4 through 7) Saturday through Tuesday...

The Eastern Bering upper level low continues to ooze its way
Southeastward across the Alaska Peninsula, into and across the
Gulf of Alaska through the beginning of the week. A rather
energetic impulse over Northwestern Alaska helps flatten a Western
Bering ridge, and draw a trough back into the Bering through the
weekend, and helps establish a link-up with a second low out of
the Russian Far East through Tuesday. With smaller troughs and
weak surface low centers rotating through the pattern along the
Aleutians, periods of rainfall are expected over the Aleutians,
AKPEN, Kodiak Island and the Southern Kenai Peninsula through the
forecast period.

- Kutz

&&

.AVIATION...

PANC...VFR conditions will persist through at least this
afternoon. Southeast winds will likely briefly reach back into the
terminal ahead of a weakening front approaching form the southwest
this afternoon, but should stay much weaker compared to
yesterday evening. Winds will weaken and become southwesterly as
the front moves past this evening. Rain showers will also move in
as the winds shift around, potentially lowering ceilings into
MVFR range this evening into tonight as a push of low level
moisture moves up the Cook Inlet behind the front.

&&


$$